Fences are generally designed to prevent people, animals, etc. from leaving and accessing a particular area. Mechanical fences, such as chain-link and barbed wire, can be scaled if not continuously monitored. Continuous monitoring, however, is not always possible. For example, some fences stretch relatively long lengths of land, such as the case with national border fences. There is simply not enough manpower, nor is it economically feasible, to physically and continuously monitor the entire length of these fences.
Lasers can be used in determining intrusions by detecting a break in a beam. For example, a laser may be in continuous optical communication with a detector. If an intruder crosses the beam, then the detector may trigger an alarm. However, these detection systems do not provide any identification of the intrusion. Rather, they merely indicate that some form of intrusion has taken place. As such, animals or moving objects can trigger false alarms. Moreover, these detection systems do not function well in the outdoors due to the presence of ambient light (e.g., sunlight) so they are generally not able to provide any type of “fencing”.